Nonwoven abrasive products are generally made by applying an abrasive coating to a nonwoven substrate and curing the abrasive coating. Suitable nonwoven substrates may be provided by processes such as carded, air laid, spunbond, or wet laid processes. Nonwoven substrates may be needletacked to densify and mechanically-entangle constituent fibers. Initial “prebond” coatings may be applied and cured to stabilize the nonwoven substrate prior to further processing. Abrasive coatings or layers, which include a curable (hardenable) binder and abrasive particles, are applied to the nonwoven substrate to form the abrasive product.
Low density abrasive products of the type defined in U.S. Pat. No. 2,958,593 and sold under the registered trademark “SCOTCH-BRITE” by 3M Company of St. Paul, Minn., have found significant commercial success as surface treatment products. This type of abrasive product is typically formed of crimped staple fibers which have been formed into a mat and impregnated with resinous binder and abrasive. This material is made available commercially in a wide variety of types to provide many functions.
Common forms for nonwoven abrasive products are a disc or wheel for mounting on a rotating axis, a belt, a pad for finishing equipment, such as floor treating pads or a sheet for use as a hand pad. The abrasive article may be attached to a support during use, such as a back-up pad for a grinder, or, the abrasive article may include sufficient volume to use as a hand pad.
In certain applications, nonwoven abrasive discs are preferred over coated abrasive discs, which generally have a cloth, paper or plastic backing, because the nonwoven discs are more conformable to the surface being finished. For example a nonwoven abrasive disc easily conforms around sharp corners and welds without tearing the disc or gouging the surface being finished. This conformability has its disadvantages for some applications, as the nonwoven discs usually have lower grinding characteristics (e.g., cut rate) than coated abrasive discs.
What is desired are nonwoven abrasive articles that retain the conformable aspects of nonwoven abrasive articles but have increased cut performance.